He continued, “It's easy to change the amount and location of energy. I can heat up the ears if you'd like some corn on the cob. Or, since it's nearly time for breakfast, I could turn them into cornflakes for you.”
Her wordless gaze made him uneasy. “I could listen to what you're thinking, but I won't. I won't misuse my power, I'll only use it to do good things! Say you believe in me!”
For a moment a brilliant blue dot peeked through the clouds, shining like a shard of lapis lazuli. Martin pointed at it and said, “Think of all the people there who are suffering because of violence and natural disasters. Millions more are sick or dying. I can protect the innocent, end disease and death, even make the old young again!
“Yes, I know we'll have to think through the consequences of doing that first. There'd be all sorts of social, economic, and political repercussions if I did it right away. But we're both clever enough and care enough about what happens to humanity to solve every problem that comes up.”
Katerina whispered, “No, Martin. Neither of us, not even the whole human race is smart enough or good enough to handle that much power all at once. Even with the best intentions you could cause more tragedy on Earth than we already have. I gave my life rather than accept the aliens’ ‘gift,’ because I wasn't sure I could resist the temptation to remake the world in my own image. I'll do whatever I must to prevent you from remaking it in yours.
“You're a good man, Martin. But not even the best man is good enough to be a god.”
His finger stabbed at the golden cross hanging from her neck. “I thought you believed someone could save the human race by being both man and god.”
“He was God and became man. Not the other way around. That makes all the difference.”
Martin scowled. “There's no point arguing. Let's both cool off for now. We can decide what to do later.”
“I'm sorry, Martin. I'm afraid I can't do that.”
He snickered. At least one of the classic SF movies he'd shown Katerina during their flight to Mars had made an impression on her. “And how are you going to keep the pod bay doors closed from me?"
When she didn't answer, he turned away and looked out over the barren plain. He pictured it lush and viridescent with vast fields of crops—dwarfing the tiny garden they'd slowly and laboriously planted themselves. Perhaps Mars could be the breadbasket for a new, immortal human race—
Then he sensed it—an alien presence nearby. He looked around for the hazy scintillating lights—listening for the aliens to speak to him a third time.
He saw and heard nothing. Then he realized where his impression of an alien presence was coming from.
It came from Katerina.
Martin stared open-mouthed as the cornstalks whose growth he'd accelerated shrank back to their original size. An alien voice that sounded like Katerina's murmured, “The only way to stop you was to become as powerful as you. And God forgive me if I've made the wrong choice!”
As the horizon slowly brightened, a cold misty rain began to fall. It splattered against two lonely figures standing far apart on a rusty plain no longer home to anything merely human. Both had survived to gaze at another wondrous, mystical Martian dawn.
But the eyes that looked out over this dawn were no longer innocent.
Copyright (c) 2008 H. G. Stratmann
(EDITOR'S NOTE: Katerina and Martin first appeared in “The Paradise Project.” [November 2007])
[Back to Table of Contents]
* * *
Reader's Department: IN TIMES TO COME
Our October issue features two quite different novelettes: “New Wineskins,” by Richard A. Lovett and Mark Niemann-Ross, and “Stealing Adriana,” by Dave Creek. One is chillingly plausible and close to home, about a journalist who wanders into a scene that seems a little too idyllic to be true—and it is, concealing a sinister new twist on a (relatively) old problem. The other is distant and exotic, in time, distance, and technology, a tale of new human abilities at cross purposes on an alien world. Both are thoroughly engaging, entertaining, and thought-provoking.
The rest of the fiction includes short stories by Robert R. Chase and Carl Frederick (I'll leave it to you to guess which one[s] might be considered “seasonal") and the climax and conclusion of David R. Palmer's Tracking.
Richard A. Lovett also supplies the fact article, “Here There Be Dragons: The Ivory-Billed Woodpecker and Other Mysteries of an Explored Planet.” Obviously a planet being visited for the first time will be full of mysteries and surprises; but the recent (and still controversial) rediscovery of the ivorybill is but one example of how even our own planet may still have tricks up its sleeve, even though our kind has been exploring it for hundreds of thousands of years.
[Back to Table of Contents]
* * *
Science Fact: FOLLOW THE NANOBRICK ROAD
by Edward M. Lerner
Perhaps like many Analog readers, I first encountered nanotech in the pages of this magazine. The 1987 science-fact article “Nanotechnology,” coauthored by Chris Peterson and K. Eric Drexler, was a real eye-opener. I rushed to find a copy of Drexler's 1986 science popularization Engines of Creation: The Coming Era of Nanotechnology. (My haste was unnecessary—the book continues to sell well.)[1]
Two decades later, nanotech has become big business. And too important to be left to business: The federal government (and many governments around the world) invests heavily in related R&D. The National Nanotechnology Initiative has spent 6.5 billion dollars over five years, with spending continuing to ramp up. A National Science Foundation expert foresees 1 trillion dollars in annual worldwide production of nanotech-related goods by 2015.[2]
* * * *
What is nanotech?
Nanotechnology is most simply defined as engineering or manufacturing performed at the scale of nanometers. A nanometer, abbreviated nm, equals one billionth, 10-9, of a meter. For those who prefer classical standards of reference, human hairs vary in diameter from about 10,000 to about 100,000 nm.
“Small stuff” is insufficient to explain the allure of nanotech, and the billions in public investment. While it's easy to find products labeled as nanotech, in categories from:
—sun block (with active ingredients in the form of 30-nm particles of zinc oxide), to
—clothing (whose fibers have been nanocoated for stain resistance or antistatic properties), to
—golf clubs (made lighter and more flexible by embedding carbon nanotubes in the composite material of the shaft), what really excites people is the potential for far more sophisticated applications.
Individual atoms are tenths of a nanometer in size.[3] The allure of nanotech is atomically precise engineering, and not merely of static materials. The title of Drexler's book speaks of engines, not golf clubs. Now imagine what might be done with truly tiny engines built with atomic precision....
* * * *
The road to nanotech
I recently attended a conference organized by the Foresight Nanotech Institute (cofounded by Drexler in 1986), Battelle Labs (the not-for-profit R&D entity that administers several national labs), and the Society of Manufacturing Engineers. This article draws heavily, but not exclusively, on the conference[4] to illustrate the progress and promise in nanotech.
An ambitious purpose was reflected in the conference title, “Productive Nanosystems: Launching the Technology Roadmap.” We'll return to that curious qualifier: productive. As for “roadmap,” the allusion is to one of the most successful case histories of industrial policy, the International Technology Roadmap for Semiconductors (ITRS).[5]
Manufacturers and customers alike grew reliant on predictable advances in integrated-circuit technology, and the promise that chips will steadily grow more feature-packed (and hence faster, smaller, and cheaper). We call that forecast Moore's Law, but it's hardly a law of nature.[6] Maintaining that rate of progress takes a concerted, ongoing international collaboration among corporations, academia, and governments. Semiconductor fo
undries take years and billions of dollars to build—a misstep can doom a company. It's not surprising that the ITRS is actively supported and regularly updated.
Nanotech is a young field, far less mature than semiconductor electronics at the time of ITRS's conception. The nanotech roadmap is a daunting—and potentially invaluable—endeavor. Because nanotech is so young, to choose a path forward is challenging indeed.
* * * *
One (tiny) step at a time
Our journey begins with nanomaterials. As we've seen, some nanomaterials have already found their way into products. Not all nanomaterials require atomically precise manufacturing.
* * * *
Overview: Nanotechnology Roadmap
Nanomaterials, now/2007.
Nanocomponents, 2-10 years.
Functional nanosystems, 5-15 years.
Atomically precise productive nanosystems, 10-25 years.
Scaled APPN array systems: 15-30+ years.
* * * *
And not all applications are as inconsequential as golf clubs. Nanometer-thick films enable the giant magnetoresistance (GMR) technology that crams ever more gigabytes into disk drives.[7] Denser storage is rather handy for laptops, to cite just one benefit. Peter Gruenberg and Albert Fert received the 2007 physics Nobel for their work with GMR.
Next, consider the single-wall carbon nanotube: a sheet of graphite (a form of carbon) just one atom thick, rolled into a cylinder only one nanometer in diameter. A carbon nanotube can, in theory, extend to any length. [8] A single-wall carbon nanotube is stronger and lighter than steel and an excellent conductor of electrical current.
Despite their nanoscale aspect, nanotubes are manufactured by such brute-force methods as laser ablation and arc discharge. We can hope to weave nanotubes into a super-strong cable for a space elevator, but record-breaking nanotubes are only a few centimeters long. No space elevator for us this week....
That's our starting point. Where are we going?
The roadmap leads us first to nanocomponents. These are building blocks like motors, pumps, bearings, gears, and sensors. Nature builds nanocomponents; surely we can, too. (A bit on how comes later in this article.) Over the next decade, it is expected that researchers will build an extensive library of nanoscale components.
Interesting things can be done with just nanocomponents. David Leigh, of the University of Edinburgh, introduced a surface coated with the simplest of nanoscale motors: bistable molecules. In one position, the molecules are hydrophobic (water repelling), and in the other, hydrophilic (water attracting). Ultraviolet light flipped the molecules between states. Leigh showed a video of a one-millimeter (10-3 meter: far larger than nanoscale) water droplet on this surface. UV illumination impelled the droplet across the surface—even up a significant slope.
The next stage (five to fifteen years from now?) is functional nanosystems, combinations of nanocomponents. These systems will transform materials, information, or energy. They just won't transform much. Typical production quantities are predicted to be in the milligram range.
Next up (ten to twenty-five years out): atomically precise productive nanosystems. APPNs will introduce a new era in nanotech and manufacturing. APPNs will produce (hence the conference name) other objects with atomic precision, and do so under programmable control. The programmable control need not be onboard the APPN. By reason of safety or public relations or efficiency, it may be best if the programmable control not reside in the APPN.[9]
Squinting into the metaphorical distance (fifteen to thirty-plus years out) we come to scaled, atomically precise, productive nanosystem array systems. With these we will finally build large objects, and bulk materials, with atomic precision. Carbon nanotubes are stronger than steel because they are defect free, not because of nanoscale. Atomically precise manufacturing will let us build any material without defect—and then steel will be much stronger. Many materials can, in theory, be made two orders of magnitude stronger by suppressing defects.
* * * *
Why so vague?
The preceding section may seem less of a roadmap than a rough sketch of the territory ahead. Fair enough—and with good reason. Much of the conference dealt with alternative techniques for the first step forward: making nanocomponents.
Several methods offer promise. At the most abstract level, these boil down to biochemical and mechanical approaches—popularly, wet and dry.
Living cells teem with sophisticated molecular machinery. DNA encodes the directions to build complex and quite large structures (like us). Biology proves by example that nanotech is possible, and biologists and biochemists presented a fair number of papers at the conference.
Alas, nature can be a bit of a sluggard,[10] and many chemical processes yield unwanted byproducts. There's appeal to purposeful control over every step of building things.
Wet vs. dry was not an open issue at the conference, and Drexler cautioned in his address that it's too early to pick an approach. He stressed, in fact, that the different techniques might complement each other.
* * * *
That does not compute
It is challenging to realistically model even simple molecules.
Our senses delude us that objects have properties that can—at least in principle—be measured with absolute precision. Attributes of objects, such as their size, position, and velocity, seem continuous and infinitely divisible.
At sufficiently small scale, our intuition ceases to be valid. Electrons and nuclei are governed by quantum effects that manifest only at tiny scales. For example, the Heisenberg Uncertainty Principle tells us that location and momentum cannot both be measured to infinite precision. The more one knows about location, the less can be known—even in principle—about momentum. And vice versa.
Schrodinger'sequation describes the theoretical behavior of particles like electrons and atomic nuclei. The descriptions are probabilistic rather than determinate. Except in very artificial circumstances (like a lone electron in an infinitely deep potential well), the equation lacks exact solutions. Quantum chemists model the atomic behavior of atoms within molecules using computation-intensive approximations.[11]
Hence: The electrical forces at work among atoms (nuclei attract electrons; nuclei repel nuclei; electrons repel electrons) can be characterized only probabilistically and inexactly. The best approximations are computation-intensive, manageable for only a few atoms. Quickly enough, modelers fall back on nineteenth-century physics to do much simpler—and less precise—approximations.
How many atoms might a nanoproduct contain, and hence might we desire to model? Even for very small items, a lot. A buckyball is a hollow carbon sphere about one nm in diameter—comprised of 60 carbon atoms. A cube (of most anything solid) just five nm on a side contains tens of thousands of atoms.
The need to work with approximation upon approximation is a significant hurdle to our understanding. Nanotech is out ahead of nanoscience.
* * * *
Ramping up
The roadmap envisions eventually building macroscale objects with nanotech. Defect-free material will enable new structural applications—perhaps, finally, that space elevator. Defect-free conductors can make our power-distribution systems more efficient and reliable.
However...
A few grams of matter contain roughly a trillion trillion atoms, and we can't precisely model the behavior of two.
Computation is not the only approach, of course. David Geohegen of Oak Ridge National Labs spoke of the need for better manufacturing-level understanding of nanomaterials. Focusing on single-wall carbon nanotubes, Geohegen summarized the gaps in our knowledge of how the tubes grow and what circumstances introduce flaws. He advocated for standards (e.g., to characterize defects and purity) in nanotube production.
* * * *
Fun with atoms
Manipulation of individual atoms was first demonstrated in 1990 by Donald Eigler and Erhard Schweizer. Their employer cannot help but spring to mind. To demonstrat
e their ability to move single atoms using a scanning tunneling microscope (STM), Eigler and Schweizer released an image of thirty-five xenon atoms set onto a nickel surface, arranged into letters: IBM.
Atoms are small (xenon atoms being on the heavy end, each massing about 1.31 x 10-20 grams). Building atomically precise products one atom at a time will take ... lots of time.
One method much discussed was atomic lithography.[12] Rather than paint design patterns with light, atomic lithography uses the very fine probe tip of an STM to dislodge individual hydrogen atoms from the silicon surface. Michelle Simmons of the University of New South Wales netted in from Australia to report having built interconnects just 2.5 nm in length. In contrast, a state-of-the-art semiconductor plant makes chips with features no smaller than 45 nm.
Moore's law suggests that industry will be manufacturing chips with atomic-scale features by 2020. Simmons’ team may be blazing the trail. They have used atomic lithography and STMs to precisely implant individual phosphorus atoms into crystalline silicon. The up/down spin states of individual atoms (rather than, today, bunches of electrons stored, or not, in tiny capacitors) may eventually encode digital bits.
The next step is to marry atomic lithography with parallelism. Thomas Theis of IBM discussed a prototype 4,000-bit read/write head for very high-density (terabit/in.2) disk drives. That's getting close to thousands of individually addressable, program-controlled probe tips.
Nature is nanotechnologists’ proof by example that matter can be organized en masse by atomically precise methods, but of course we don't find STMs in nature. For another path to nanotech, we turn next to some of the biologists’ presentations.
* * * *
Nature's way
Many proteins self-assemble into complex structures, including—a very handy type of device—motors. Consider the whiplike structure called a flagellum that propels many bacteria. Amazingly, forty proteins self-assemble into a structure of bearings, rotor, drive shaft, and whip. ATP molecules (the tiny energy carriers within cells) break hydrogen bonds in the tiny engine to drive a rotary motion that flails the whip end.
Analog SFF, September 2008 Page 7
